A deformation-resistant fuel cell metal bipolar plate

Abstract

The present invention provides a deformation-resistant fuel cell metal bipolar plate, comprising: an upper unipolar plate and a lower unipolar plate of identical structure, wherein the reactive regions of the upper unipolar plate and the reactive regions of the lower unipolar plate each include a plurality of grooves and ridges, wherein the bottom of the grooves is provided with a wavy raised structure, wherein the wavy raised structure includes crests and troughs, wherein the crests and troughs are alternately connected in the form of a sine function, wherein the crests of the upper unipolar plate correspond vertically to the crests of the lower unipolar plate, and the troughs of the upper unipolar plate correspond vertically to and contact the troughs of the lower unipolar plate, and the ridges of the upper unipolar plate are provided with a plurality of arrays of indentations. The technical solution of the present invention solves the problems of insufficient rigidity and poor deformation resistance of bipolar plates in the width direction in the prior art.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and in particular to a deformation-resistant fuel cell metal bipolar plate. Background Art

[0002] At present, with the continuous improvement of the volume power density of fuel cells, metal bipolar plates tend to be thinner. As the thickness of the corresponding substrate is gradually decreasing, higher requirements are placed on the deformation resistance of the bipolar plates. In order to adapt to the development trend and ensure that the active area of ​​the metal bipolar plate has high power output capability, fuel cell manufacturers often reduce the flow channel depth and increase the flow channel width to increase the porosity of the active area, providing sufficient electrochemical reaction space for the fuel cell core. However, the consequence is that the deformability of the metal bipolar plate increases, resulting in stress concentration defects inside the bipolar plate, which not only affects the assembly effect between the multi-section bipolar plates of the stack, but also affects the assembly matching between the bipolar plate and the membrane electrode inside the stack. Although arc-shaped bosses and groove structures or bending structures are used to increase the stiffness of the bipolar plate, they do not effectively solve the problem of insufficient stiffness of the bipolar plate in the width direction. Summary of the Invention

[0003] To address the aforementioned technical issues of insufficient widthwise rigidity and poor deformation resistance of bipolar plates, a deformation-resistant fuel cell metal bipolar plate is provided. This invention primarily utilizes wave-shaped raised structures in the grooves and indentations on the upper ridge to increase the widthwise rigidity of the metal bipolar plate, thereby enhancing its deformation resistance.

[0004] The technical means adopted in the present invention are as follows:

[0005] A deformation-resistant fuel cell metal bipolar plate, comprising: an upper unipolar plate and a lower unipolar plate of identical structure;

[0006] The reactive area of ​​the upper unipolar plate and the reactive area of ​​the lower unipolar plate each include a plurality of grooves and ridges, the bottom of the groove is provided with a wavy protrusion structure, the wavy protrusion structure includes crests and troughs, and the crests and troughs are alternately connected in the form of a sine function;

[0007] The crests of the upper unipolar plate correspond vertically to the crests of the lower unipolar plate, and the troughs of the upper unipolar plate correspond vertically to and contact the troughs of the lower unipolar plate;

[0008] A plurality of arrays of indentations are provided on the back of the upper unipolar plate.

[0009] Furthermore, the groove is a linear or serpentine structure along the length direction of the bipolar plate.

[0010] Furthermore, the position of the wave crest corresponds to the position of the wave trough in the adjacent groove.

[0011] Furthermore, the height of the wave crest is smaller than the depth of the groove.

[0012] Furthermore, the bottom of the trough is level with the bottom of the groove.

[0013] Furthermore, the height of the indentations is less than 0.2 mm, the width is 1 to 4 mm, and the intervals between the indentations are 10 to 50 mm.

[0014] Furthermore, the upper unipolar plate and the lower unipolar plate are connected to form the bipolar plate by laser welding.

[0015] Compared with the prior art, the present invention has the following advantages:

[0016] 1. The present invention provides a deformation-resistant fuel cell metal bipolar plate. By providing a wavy protrusion structure in the groove and an indentation on the upper ridge, the deformation resistance of the metal bipolar plate in the width direction is improved. At the same time, the intercommunication ability of gas or liquid between adjacent flow channels in the reaction active area of ​​the bipolar plate is increased, and the uniformity of gas and temperature distribution and the drainage effect are enhanced. The use of a flow channel structure with alternating cross-sectional areas can also make the fuel cell have good assembly reliability and can output more stably under conditions of high volume power.

[0017] In summary, the technical solution of the present invention, by providing a wavy raised structure in the groove and creating an indentation on the upper ridge, increases the rigidity of the metal bipolar plate in the width direction, thereby improving the metal bipolar plate's resistance to deformation. Therefore, the technical solution of the present invention solves the problem of insufficient rigidity and poor deformation resistance in the width direction of bipolar plates in the prior art.

[0018] Based on the above reasons, the present invention can be widely promoted in the fields of fuel cells and the like. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0020] Figure 1 This is a schematic diagram of the overall structure of the anti-deformation fuel cell metal bipolar plate described in the present invention.

[0021] Figure 2 This is a schematic diagram of the partial structure of the anti-deformation fuel cell metal bipolar plate described in the present invention.

[0022] Figure 3 Schematic diagram of the positions of the crests and troughs inside the grooves of the upper and lower plates of the present invention.

[0023] Figure 4 Schematic diagram of the positions of the crests and troughs at the bottom of adjacent grooves of the monopolar plate according to the present invention.

[0024] Figure 5 Schematic diagram of the indentation structure of the present invention.

[0025] Figure 6 This is a schematic cross-sectional view of the common planar grooved bipolar plate described in Example 1 along the gas flow direction.

[0026] Figure 7 This is a schematic diagram of the BB cross section of the ordinary planar grooved bipolar plate described in Example 1.

[0027] Figure 8 This is a CC cross-sectional schematic diagram of the common planar groove bipolar plate described in Example 1.

[0028] Figure 9 This is a schematic cross-sectional view of the anti-deformation fuel cell metal bipolar plate described in Example 1 along the gas flow direction.

[0029] Figure 10 BB cross-sectional schematic diagram of the anti-deformation fuel cell metal bipolar plate described in Example 1.

[0030] In the figure: 1. Left three-cavity mouth area; 2. Left distribution area; 3. Reactive area; 300. Upper unipolar plate; 301. Upper groove; 3011. Upper plate crest; 3012. Upper plate trough; 302. Indentation; 303. Ridge I; 310. Lower unipolar plate; 311. Lower groove; 3111. Lower plate crest; 3112. Lower plate trough; 4. Right distribution area; 5. Right three-cavity mouth area. DETAILED DESCRIPTION

[0031] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0032] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0033] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0034] Unless otherwise specifically stated, the relative arrangement of the parts and steps, numerical expressions and numerical values ​​described in these embodiments do not limit the scope of the present invention. At the same time, it should be clear that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The techniques, methods and equipment known to ordinary technicians in the relevant fields may not be discussed in detail, but where appropriate, the techniques, methods and equipment should be considered as part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following figures, so once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0035] In the description of the present invention, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "horizontal, vertical, vertical, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention: the directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

[0036] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figures. For example, if the device in the drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below their position devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0037] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0038] Example 1

[0039] like Figures 1 to 6 As shown, the present invention provides a deformation-resistant fuel cell metal bipolar plate, which comprises, from left to right, a left three-cavity port area 1, a left distribution area 2, a reaction active area 3, a right distribution area 4, and a right three-cavity port area 5;

[0040] The bipolar plate comprises an upper monopolar plate 300 and a lower monopolar plate 310 of the same structure. Figure 1 The cross section in the AA direction is honeycomb-shaped;

[0041] The upper unipolar plate 300 includes a plurality of upper grooves 301 and a ridge I 303. A wavy protrusion structure I is provided at the bottom of the upper groove 301. The wavy protrusion structure I includes an upper unipolar plate crest 3011 and an upper unipolar plate trough 3012. The upper unipolar plate crest 3011 and the upper unipolar plate trough 3012 are alternately connected in the form of a sine function.

[0042] The lower unipolar plate 310 includes a plurality of lower grooves 311 and a ridge II. A wavy protrusion structure II is provided at the bottom of the lower groove 311. The wavy protrusion structure II includes a lower unipolar plate crest 3111 and a lower unipolar plate trough 3112. The lower unipolar plate crest 3111 and the lower unipolar plate trough 3112 are alternately connected in the form of a sine function.

[0043] The upper unipolar plate peaks 3011 correspond vertically to the lower unipolar plate peaks 3111 to form the honeycomb structure, and the upper unipolar plate troughs 3012 correspond vertically to and contact the lower unipolar plate troughs 3112;

[0044] The upper groove 301 is used to transmit hydrogen, the lower groove 311 is used to transmit air or oxygen, and the honeycomb structure is used to transmit coolant. The honeycomb structure can enhance the rigidity of the bipolar plate in the width direction and enhance the anti-deformation ability of the bipolar plate;

[0045] The spine 1 303 is provided with a plurality of arrays of indentations 302;

[0046] The indentations 302 can enhance the rigidity of the bipolar plate and the intercommunication capability of gas or liquid between adjacent flow channels.

[0047] Furthermore, the upper groove 301 and the lower groove 311 are linear or serpentine structures along the length direction of the bipolar plate.

[0048] Furthermore, the upper unipolar plate peak 3011 corresponds to the upper unipolar plate trough 3012 in the adjacent upper groove 301, and the lower unipolar plate peak 3111 corresponds to the lower unipolar plate trough 3112 in the adjacent lower groove 311, which is mainly used to make the fluid pressure in adjacent grooves different, thereby facilitating the diffusion of the fluid into adjacent flow channels.

[0049] Furthermore, the heights of the upper unipolar plate crest 3011 and the lower unipolar plate crest 3111 are smaller than the depths of the upper groove 301 and the lower groove 311 .

[0050] Furthermore, the bottoms of the upper unipolar plate trough 3012 and the lower unipolar plate trough 3112 are level with the lower edges of the upper groove 301 and the lower groove 311 .

[0051] Furthermore, the height of the indentations 302 is less than 0.2 mm, the width is 1 to 4 mm, and the intervals between the indentations 302 are 10 to 50 mm.

[0052] Furthermore, the upper unipolar plate 300 and the lower unipolar plate 310 are connected by laser welding.

[0053] The principle of increasing the rigidity of the reactive active area in the width direction of the anti-deformation fuel cell metal bipolar plate of the present invention is as follows: the rigidity of the weaker area of ​​the ordinary planar groove bipolar plate is as follows: Figure 4 As shown, the BB section is as follows Figure 5 As shown, calculate the maximum bending stress of the BB section:

[0054]

[0055] Where: M represents the bending moment;

[0056] b represents the cross-section width;

[0057] h represents the cross-section height;

[0058] CC cross section Figure 6 As shown, calculate the maximum bending stress of CC section:

[0059]

[0060] Where: M represents the bending moment;

[0061] b represents the cross-section width;

[0062] H represents the outer height of the cross section;

[0063] H represents the height within the cross section;

[0064] With the values ​​of M and b fixed, and assuming H = 1 mm and h = 0.2 mm, the maximum stresses of the BB and CC sections of the ordinary planar grooved bipolar plate are calculated respectively:

[0065]

[0066] It can be seen that the stress of the BB section is greater than the stress of the CC section, indicating that the deformation resistance of the BB section is poor. The stiffness of the anti-deformation fuel cell metal bipolar plate of the present invention is relatively weak. Figure 7 As shown, the BB section is as follows Figure 8 As shown, calculate the maximum stress of BB section:

[0067]

[0068] Where: M represents the bending moment;

[0069] y max Indicates the maximum displacement of the cross section from the Z axis;

[0070] A represents the integration area;

[0071] Further derivation of the formula shows that:

[0072]

[0073] Wherein: h* is the equivalent height of the curved groove structure. It is obvious that h*>h. Assuming h*=1.5h, the maximum bending stress of the bipolar plate described in the present invention at the groove structure is 0.4 times the maximum bending stress of the ordinary plane groove bipolar plate. It can be seen that the deformation-resistant fuel cell metal bipolar plate described in the present invention has greater rigidity and deformation resistance.

[0074] The present invention provides a deformation-resistant fuel cell metal bipolar plate, which can improve the stiffness of the bipolar plate in the width direction and the battery assembly consistency, and can enable the fuel cell to output stable performance under high volume power conditions; specifically, by setting a sinusoidal wave convex structure in the groove, the deformation resistance of the bipolar plate is effectively increased, and the matching consistency between the bipolar plate and the membrane electrode during the battery assembly process is improved; and the longitudinal section of the groove has flow channels with alternating cross-sectional areas along the gas transmission direction, which is beneficial to improving the gas transmission efficiency to the membrane electrode, improving the discharge performance of the battery core, and enhancing the drainage effect; an array of distributed indentations 302 is opened on the upper ridge I 303, which can increase the stiffness of the bipolar plate and the intercommunication ability of gas or fluid between adjacent flow channels.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A deformation-resistant fuel cell metal bipolar plate, characterized in that: include: Upper unipolar plate and lower unipolar plate with identical structure; The reactive area of ​​the upper unipolar plate and the reactive area of ​​the lower unipolar plate each include a plurality of grooves and ridges, the bottom of the groove is provided with a wavy protrusion structure, the wavy protrusion structure includes crests and troughs, and the crests and troughs are alternately connected in the form of a sine function; The peaks of the upper unipolar plate correspond vertically to the peaks of the lower unipolar plate, forming a honeycomb structure, and the troughs of the upper unipolar plate correspond vertically to and contact the troughs of the lower unipolar plate; A plurality of arrays of indentations are provided on the back of the upper unipolar plate; The height of the wave crest is less than the depth of the groove; The bottom of the trough is level with the bottom of the groove.

2. The anti-deformation fuel cell metal bipolar plate according to claim 1, characterized in that: The grooves are in a straight or serpentine structure along the length direction of the bipolar plate.

3. The anti-deformation fuel cell metal bipolar plate according to claim 1, characterized in that: The wave crest position corresponds to the wave trough position in the adjacent groove.

4. The anti-deformation fuel cell metal bipolar plate according to claim 1, characterized in that: The height of the indentations is less than 0.2 mm, the width is 1 to 4 mm, and the intervals between the indentations are 10 to 50 mm.

5. The anti-deformation fuel cell metal bipolar plate according to claim 1, characterized in that: The upper unipolar plate and the lower unipolar plate are connected to form the bipolar plate by laser welding.

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